diff --git a/vchan/io.c b/vchan/io.c
index e735c86a..17a3abe3 100644
--- a/vchan/io.c
+++ b/vchan/io.c
@@ -125,6 +125,12 @@ int libvchan_write(struct libvchan *ctrl, char *data, int size)
 {
 	int avail, avail_contig;
 	int real_idx;
+#ifdef WINNT
+	// because of mask-on-fire and do_notify called previously, evtchn must be
+	// unmasked before libvchan_wait. Do it before checking if data is
+	// available to prevent race
+	libvchan_prepare_to_select(ctrl);
+#endif
 	while ((avail = libvchan_buffer_space(ctrl)) == 0)
 		if (libvchan_wait(ctrl) < 0)
 			return -1;
@@ -150,6 +156,12 @@ int libvchan_read(struct libvchan *ctrl, char *data, int size)
 {
 	int avail, avail_contig;
 	int real_idx;
+#ifdef WINNT
+	// because of mask-on-fire and do_notify called previously, evtchn must be
+	// unmasked before libvchan_wait. Do it before checking if data is
+	// available to prevent race
+	libvchan_prepare_to_select(ctrl);
+#endif
 	while ((avail = libvchan_data_ready(ctrl)) == 0)
 		if (libvchan_wait(ctrl) < 0)
 			return -1;